<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // "use strict"
        // function fn(a,a){
        //     console.log(this);
        // }
        // fn(1,2);
        var str = 'asdgsda' ;
        console.log(str.search('a'));
    </script>
</body>
</html>